[ECO-5386] Added impl. for LiveObjectSerializer interface

1. Implemented JsonSerializetion using gson library
2. Implemented MsgpackSerialization without external dependency
3. Annotated/updated ObjectMessage fields for gson serialization
4. Added msgpack dependency to liveobjects

Author: sacOO7

live-objects/build.gradle.kts

@@ -11,6 +11,7 @@ repositories {
 
 dependencies {
     implementation(project(":java"))
+    implementation(libs.bundles.common)
     implementation(libs.coroutine.core)
 
     testImplementation(kotlin("test"))

live-objects/src/main/kotlin/io/ably/lib/objects/Helpers.kt

@@ -39,18 +39,18 @@ internal enum class ProtocolMessageFormat(private val value: String) {
   override fun toString(): String = value
 }
 
-internal class Binary(val data: ByteArray?) {
+internal class Binary(val data: ByteArray) {
   override fun equals(other: Any?): Boolean {
     if (this === other) return true
     if (other !is Binary) return false
-    return data?.contentEquals(other.data) == true
+    return data.contentEquals(other.data)
   }
 
   override fun hashCode(): Int {
-    return data?.contentHashCode() ?: 0
+    return data.contentHashCode()
   }
 }
 
 internal fun Binary.size(): Int {
-  return data?.size ?: 0
+  return data.size
 }

live-objects/src/main/kotlin/io/ably/lib/objects/ObjectMessage.kt

@@ -3,6 +3,12 @@ package io.ably.lib.objects
 import com.google.gson.JsonArray
 import com.google.gson.JsonObject
 
+import com.google.gson.annotations.JsonAdapter
+import com.google.gson.annotations.SerializedName
+import io.ably.lib.objects.serialization.InitialValueJsonSerializer
+import io.ably.lib.objects.serialization.ObjectDataJsonSerializer
+import io.ably.lib.objects.serialization.gson
+
 /**
  * An enum class representing the different actions that can be performed on an object.
  * Spec: OOP2
@@ -28,19 +34,14 @@ internal enum class MapSemantics(val code: Int) {
  * An ObjectData represents a value in an object on a channel.
  * Spec: OD1
  */
+@JsonAdapter(ObjectDataJsonSerializer::class)
 internal data class ObjectData(
   /**
    * A reference to another object, used to support composable object structures.
    * Spec: OD2a
    */
   val objectId: String? = null,
 
-  /**
-   * Can be set by the client to indicate that value in `string` or `bytes` field have an encoding.
-   * Spec: OD2b
-   */
-  val encoding: String? = null,
-
   /**
    * String, number, boolean or binary - a concrete value of the object
    * Spec: OD2c
@@ -217,11 +218,13 @@ internal data class ObjectOperation(
    * the initialValue, nonce, and initialValueEncoding will be removed.
    * Spec: OOP3h
    */
+  @JsonAdapter(InitialValueJsonSerializer::class)
   val initialValue: Binary? = null,
 
   /** The initial value encoding defines how the initialValue should be interpreted.
    * Spec: OOP3i
    */
+  @Deprecated("Will be removed in the future, initialValue will be json string")
   val initialValueEncoding: ProtocolMessageFormat? = null
 )
 
@@ -312,7 +315,7 @@ internal data class ObjectMessage(
    * or validation of the @extras@ field itself, but should treat it opaquely, encoding it and passing it to realtime unaltered
    * Spec: OM2d
    */
-  val extras: Any? = null,
+  val extras: JsonObject? = null,
 
   /**
    * Describes an operation to be applied to an object.
@@ -328,6 +331,7 @@ internal data class ObjectMessage(
    * the `ProtocolMessage` encapsulating it is `OBJECT_SYNC`.
    * Spec: OM2g
    */
+  @SerializedName("object")
   val objectState: ObjectState? = null,
 
   /**

live-objects/src/main/kotlin/io/ably/lib/objects/Serialization.kt

@@ -0,0 +1,46 @@
+@file:Suppress("UNCHECKED_CAST")
+
+package io.ably.lib.objects.serialization
+
+import com.google.gson.*
+import io.ably.lib.objects.*
+
+import io.ably.lib.objects.ObjectMessage
+import org.msgpack.core.MessagePacker
+import org.msgpack.core.MessageUnpacker
+
+/**
+ * Default implementation of {@link LiveObjectSerializer} that handles serialization/deserialization
+ * of ObjectMessage arrays for both JSON and MessagePack formats using Jackson and Gson.
+ * Dynamically loaded by LiveObjectsHelper#getLiveObjectSerializer() to avoid hard dependencies.
+ */
+@Suppress("unused") // Used via reflection in LiveObjectsHelper
+internal class DefaultLiveObjectSerializer : LiveObjectSerializer {
+
+  override fun readMsgpackArray(unpacker: MessageUnpacker): Array<Any> {
+    val objectMessagesCount = unpacker.unpackArrayHeader()
+    return Array(objectMessagesCount) { readObjectMessage(unpacker) }
+  }
+
+  override fun writeMsgpackArray(objects: Array<out Any>, packer: MessagePacker) {
+    val objectMessages: Array<ObjectMessage> = objects as Array<ObjectMessage>
+    packer.packArrayHeader(objectMessages.size)
+    objectMessages.forEach { it.writeMsgpack(packer) }
+  }
+
+  override fun readFromJsonArray(json: JsonArray): Array<Any> {
+    return json.map { element ->
+      if (element.isJsonObject) element.asJsonObject.toObjectMessage()
+      else throw JsonParseException("Expected JsonObject, but found: $element")
+    }.toTypedArray()
+  }
+
+  override fun asJsonArray(objects: Array<out Any>): JsonArray {
+    val objectMessages: Array<ObjectMessage> = objects as Array<ObjectMessage>
+    val jsonArray = JsonArray()
+    for (objectMessage in objectMessages) {
+      jsonArray.add(objectMessage.toJsonObject())
+    }
+    return jsonArray
+  }
+}

live-objects/src/main/kotlin/io/ably/lib/objects/serialization/DefaultSerialization.kt

@@ -0,0 +1,99 @@
+package io.ably.lib.objects.serialization
+
+import com.google.gson.*
+import io.ably.lib.objects.Binary
+import io.ably.lib.objects.MapSemantics
+import io.ably.lib.objects.ObjectData
+import io.ably.lib.objects.ObjectMessage
+import io.ably.lib.objects.ObjectOperationAction
+import io.ably.lib.objects.ObjectValue
+import java.lang.reflect.Type
+import java.util.*
+import kotlin.enums.EnumEntries
+
+// Gson instance for JSON serialization/deserialization
+internal val gson = GsonBuilder()
+  .registerTypeAdapter(ObjectOperationAction::class.java, EnumCodeTypeAdapter({ it.code }, ObjectOperationAction.entries))
+  .registerTypeAdapter(MapSemantics::class.java, EnumCodeTypeAdapter({ it.code }, MapSemantics.entries))
+  .create()
+
+internal fun ObjectMessage.toJsonObject(): JsonObject {
+  return gson.toJsonTree(this).asJsonObject
+}
+
+internal fun JsonObject.toObjectMessage(): ObjectMessage {
+  return gson.fromJson(this, ObjectMessage::class.java)
+}
+
+internal class EnumCodeTypeAdapter<T : Enum<T>>(
+  private val getCode: (T) -> Int,
+  private val enumValues: EnumEntries<T>
+) : JsonSerializer<T>, JsonDeserializer<T> {
+
+  override fun serialize(src: T, typeOfSrc: Type, context: JsonSerializationContext): JsonElement {
+    return JsonPrimitive(getCode(src))
+  }
+
+  override fun deserialize(json: JsonElement, typeOfT: Type, context: JsonDeserializationContext): T {
+    val code = json.asInt
+    return enumValues.first { getCode(it) == code }
+  }
+}
+
+internal class ObjectDataJsonSerializer : JsonSerializer<ObjectData>, JsonDeserializer<ObjectData> {
+  override fun serialize(src: ObjectData, typeOfSrc: Type?, context: JsonSerializationContext?): JsonElement {
+    val obj = JsonObject()
+    src.objectId?.let { obj.addProperty("objectId", it) }
+
+    src.value?.let { value ->
+      when (val v = value.value) {
+        is Boolean -> obj.addProperty("boolean", v)
+        is String -> obj.addProperty("string", v)
+        is Number -> obj.addProperty("number", v.toDouble())
+        is Binary -> obj.addProperty("bytes", Base64.getEncoder().encodeToString(v.data))
+        // Spec: OD4c5
+        is JsonObject, is JsonArray -> {
+          obj.addProperty("string", v.toString())
+          obj.addProperty("encoding", "json")
+        }
+      }
+    }
+    return obj
+  }
+
+  override fun deserialize(json: JsonElement, typeOfT: Type?, context: JsonDeserializationContext?): ObjectData {
+    val obj = if (json.isJsonObject) json.asJsonObject else throw JsonParseException("Expected JsonObject")
+    val objectId = if (obj.has("objectId")) obj.get("objectId").asString else null
+    val encoding = if (obj.has("encoding")) obj.get("encoding").asString else null
+    val value = when {
+      obj.has("boolean") -> ObjectValue(obj.get("boolean").asBoolean)
+      // Spec: OD5b3
+      obj.has("string") && encoding == "json" -> {
+        val jsonStr = obj.get("string").asString
+        val parsed = JsonParser.parseString(jsonStr)
+        ObjectValue(
+          when {
+            parsed.isJsonObject -> parsed.asJsonObject
+            parsed.isJsonArray -> parsed.asJsonArray
+            else -> throw JsonParseException("Invalid JSON string for encoding=json")
+          }
+        )
+      }
+      obj.has("string") -> ObjectValue(obj.get("string").asString)
+      obj.has("number") -> ObjectValue(obj.get("number").asDouble)
+      obj.has("bytes") -> ObjectValue(Binary(Base64.getDecoder().decode(obj.get("bytes").asString)))
+      else -> throw JsonParseException("ObjectData must have one of the fields: boolean, string, number, or bytes")
+    }
+    return ObjectData(objectId, value)
+  }
+}
+
+internal class InitialValueJsonSerializer : JsonSerializer<Binary>, JsonDeserializer<Binary> {
+  override fun serialize(src: Binary, typeOfSrc: Type?, context: JsonSerializationContext?): JsonElement {
+    return JsonPrimitive(Base64.getEncoder().encodeToString(src.data))
+  }
+
+  override fun deserialize(json: JsonElement, typeOfT: Type?, context: JsonDeserializationContext?): Binary {
+    return Binary(Base64.getDecoder().decode(json.asString))
+  }
+}